Marin and federal drug investigators arrested a San Rafael merchant on allegations of selling methamphetamine from his storefront in a bust Wednesday that also netted a suspected drug trafficker in Daly City.

Both men were expected to appear in federal court on Thursday to face indictments on drug charges. Investigators also seized suspected meth and cocaine in quantities that were still being tabulated.

The arrests capped a one-year investigation that was started by the Marin County Major Crimes Task Force and eventually joined by the federal Drug Enforcement Administration and the U.S. attorney's office in San Francisco.

The merchant was identified as Alfredo Lopez, 50, the proprietor of the Azteca Market at 555 Francisco Boulevard East. Lopez was arrested Wednesday afternoon after a stream of law enforcement vehicles arrived outside the market, which sits in the back of the Harbor Center shopping complex.

Macias, 24, sat on the curb in a Livestrong athletic shirt and shorts while investigators searched his Audi in the parking lot. Then investigators searched his residence on Third Avenue and a Bruno Avenue residence where he was suspected of stashing drugs, said Sgt. Pierre Ahuncain of the Marin County Major Crimes Task Force. The alleged stash house is about a block from Jefferson High School.

Ahuncain said drug users were regularly buying meth from the Azteca Market in various quantities. Investigators suspect that proceeds from the drug sales were deposited into a cash machine at Azteca and wired to Mexico.

The investigation into the Azteca Market led agents to identify Macias as the suspected drug supplier. Macias is believed to be from the Apatzingan region of Mexico, an area of entrenched cartel activity.